Add travis config

.travis.yml

+language: python
+
+python:
+  - "2.6"
+  - "2.7"
+
+env:
+  - DJANGO=https://github.com/django/django/zipball/master
+  - DJANGO=django==1.4.1 --use-mirrors
+  - DJANGO=django==1.3.3 --use-mirrors
+
+install:
+  - pip install $DJANGO 
+  - pip install -e . --use-mirrors
+  - pip install -r requirements.txt
+
+script:
+  - python setup.py test